Water-soluble container

ABSTRACT

A water-soluble container ( 1 ) has at least one discrete chamber ( 30, 31; 130, 131 ) for containing product. At least part ( 20, 27 ) of the entirety ( 125   a,    125   b ) of a container wall ( 11, 25; 125   a,    125   b ) of the at least one chamber dissolves before the remainder of the chamber dissolves to allow product to escape.

The present invention relates generally to a water-soluble container.

Water-soluble containers as such are well-known and have a variety ofuses, such as in clothes washing. For example, CA 1112534 describes awater-soluble container for a detergent composition. The water-solublematerial may be, for example, polyvinyl alcohol (PVOH). This documentdescribes a single chamber with a film form wall of constant thickness.Because the chamber wall is of constant thickness, the entire wall mustbe dissolved before any product can escape. In certain circumstancesproduct may be required quickly, before the time when the entirecontainer has dissolved.

According to the present invention there is provided a water-solublecontainer comprising one or more discrete chambers for containingproduct, at least part of the wall of the or at least one of thechamber/s is adapted to dissolve before the remainder of the chamber toallow product to escape. This means that product can escape from achamber without requiring complete dissolution of the chamber. This canbe useful for decreasing the time taken for product to be released. Itcan also allow for a greater degree of control over when product isreleased because the area required to be dissolved is reduced.

A container according to the present invention with more than onechamber gives the possibility for a system combining the advantage ofnot requiring a whole chamber to dissolve before a product is released,together with the possibility of sequential release of products. In itssimplest form a chamber provided with the means for allowing product toescape before complete dissolution could be associated with a chambernot having those means. More complicated systems could involve chamberswhich allow products to escape after different times before completedissolution.

The ability of such containers to provide for sequential release ofmultiple products is extremely useful. For example, clothing washingusually includes a detergent stage and a stage later in the washingcycle in which a softening agent is introduced. Dish-washing sometimesincludes a detergent stage and a separate rinsing stage. In many casesit would be preferable and sometimes essential for different stages ofwashing operations to be kept completely separate.

By providing for sequential release of products the present inventionremoves the need for manual intervention at different stages of washingcycles and allows the complete washing product to be packaged andsupplied together.

The at least part of the wall will most usually be an exterior surfaceof the container thereby releasing product from the container when itdissolves. However, it is also possible that the at least part of thewall forms part of a chamber which is housed within another chamberwhich itself includes water, whereby the contents of the chambers aremixed when the at least part of the wall dissolves. This might beuseful, for example, if the product in the inner chamber is activated byproduct in the outer chamber. This allows activation in a controlledenvironment before the activated product is released into the exteriorof the container and could be useful for products which become unstableonce activated.

There are many ways in which the container could be formed in order thatproduct is released from the chamber when the part of the walldissolves. For example the part of the wall could itself comprise aclosure part which dissolves to form an opening in the chamber.

Alternatively, the part of the wall may define a releasable part. Whenthe part of the wall dissolves the releasable part is released, itselfas yet undissolved, to form an opening in the chamber. For example, thereleasable part may be a panel and the at least part of the wall atleast partly surrounds the panel so that it is released, eithercompletely or partially, when the part of the wall dissolves.Alternatively the part of the wall may comprise one or more clipelements, such as a hook. The clip elements initially clip the closurepart to the container but then dissolve and release the releasable part.In this way only a small section of the wall dissolves and yet a largeopening can be provided quickly.

There are many ways in which the part of the wall could be formed inorder that it dissolves before the remainder of the container. Forexample, the at least part of the wall could be made from a thinnersection of material and/or from a different material with a faster rateof dissolution than the remainder of the container.

In embodiments where the at least part of the wall is thinner than theremainder of the container the material thinning may be arranged on theinterior surface of the chamber wall. This is particularly relevant whenthe at least part of the wall defines a thin channel, because if thematerial thinning was arranged on the exterior surface the channel couldbecome saturated with dissolved material, which would impede furtherdissolution.

In order to simplify production and allow for high volume production thecontainer may be formed by injection moulding. In embodiments where theat least part of the wall is a thin section surrounding a panel, thearea of the panel may form the gate region for injection moulding. Thisensures that the thin section is correctly moulded by avoiding problemswith moulded regions which are remote from the injection point.

As stated above, differential dissolution characteristics may beachieved by forming the container from two or more different materialsat least some of which are water-soluble. It may, however, be preferablefor simplification of the production process for the whole of thecontainer to be formed from the same material.

In some embodiments at least part of the material from which thecontainer is formed is a polyvinyl alcohol. Alternatively at least partof the material may be a polylactic acid or a starch based material.

The container may be flexible. This may be as a result of the choice ofmaterial and/or the thickness of the walls.

Where a container has several walls, the term “wall” can refer to anyone or more of the walls. A spherical container, for example, has asingle wall whereas a cube has six walls. The term is therefore genericand could refer to any part of the material defining the chamber.

The present invention will now be more particularly described, by way ofexample, with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a housing formed as part of a containeraccording to a first embodiment;

FIG. 2 is a section along line II-II of FIG. 1,

FIG. 3 shows the housing of FIG. 2 with a lid component attached;

FIG. 4 shows the container of FIG. 3 following an initial exposure towater;

FIG. 5 is a section through a container according to an alternativeembodiment;

FIG. 6 is a section of a container according to an alternativeembodiment; and

Referring first to FIGS. 1 and 2 there is shown a housing 10 ofgenerally parallelopiped shape comprising a base wall 11, side walls 12,13 and end walls 14, 15. The housing is hollow and is open opposite thebase 11 to form a tray-like structure. The housing 10 is formed from awater-soluble material. The material could be, for example, a grade ofPVOH which dissolves at approximately 50° C. The interior of the housing10 is divided into two discrete chambers 30, 31 by spaced parallelpartition side walls 16, 17 which extend from end wall 15 and are joinedat their ends by a partition end wall 18. Each of the partition walls16, 17, 18 extends the full height of the housing walls 11, 12, 13, 14,15. The portion of the base wall 14 which is bounded by the partitionwalls 16, 17, 18 includes a panel 19 surrounded by a region of materialthinning 20 the purpose of which will be described in more detail below.

Referring now to FIG. 3 the housing of FIGS. 1 and 2 is shown formingpart of a container 1. The housing 10 is closed by a lid 25. Thechambers 30, 31 are filled with different products before the lid 25 isapplied. The lid 25 includes a panel 26 and region of material thinning27 opposite and identical to those of the housing 10. The lid 25 may besecured to the housing 10 by any convenient means such as weldingadhesion, interference fit or clipping. In this embodiment the seal is aface seal bond which is chemically activated, in this case by water, andsupported internally by a wall 28 depending from the lid 25.

In this embodiment the thickness of the housing walls and the lid isapproximately 0.4 mm. This is about the thinnest that material can bewithout a risk of ‘pin holes’ i.e. tiny holes in the material whichcould compromise the integrity of the chamber. The material thinningsare approximately 0.15 mm thick and are formed by reducing a small partof the uniform thickness of the container.

In use, the container 1 is placed in an aqueous environment and thetemperature is raised beyond the dissolution temperature of thecontainer material. As the container 1 begins to dissolve the materialthinned regions 20, 27 will completely dissolve before the remainder ofthe container. As a result, the panels 19, 26 are released from the lid25 and the base wall 14 such that product can escape from the chamber31. Of course the panels 19,26 do not have to be completely released tobe effective. For example the material thinned regions 20, 27 couldextend part way round the panels 19, 26 such that the panels 19, 26become flaps which hinge open. Product from the chamber cannot escapeuntil the remainder of the container has dissolved.

Referring now to FIG. 5 there is shown an alternative embodiment. Inthis embodiment two discrete chambers 130,131 are formed from twoseparate, hollow cube-shape housings 110 a, 110 b which are bondedtogether along adjacent side walls 112 a, 112 b. Each housing 110 a, 110b is open along one side but closed by a lid 125 a, 125 b, in thisembodiment sealed to the housings by adhesion. The lids 125 a, 125 b areformed from different grades of PVOH which dissolve at different rates,with the material of the lid 125 a having the faster dissolution rate.In this embodiment therefore the lid 125 a of the housing 110a dissolvesbefore the lid of housing 110 b, to allow its product to escape first.

Referring to FIG. 6 there is shown a container 201 with a single chamber230. A generally cuboid housing 210 comprises a base wall 211 and sidewalls 214, 215. An open side of the housing 210 is closed by a lid 225.

The lid 225 is held onto the housing 210 by a clip 220 extending fromits periphery. The clip 220 engages under a bead 235 formed around theopen side of the housing 210.

The clip 220 is thinner than the remainder of the container 201.Accordingly, in use of the container the clip 220 dissolves before theremainder of the container so that the bead 235 no longer retains thelid 225, and therefore allows the lid 225 to be released from thehousing 210.

1: A water-soluble container (1) comprising at least one discretechamber (30, 31; 130, 131) for containing product, at least a part (20,27) of a first wall (11, 25; 125 a, 125 b) of said at least one chamber30, 31; 130, 131) will dissolve before a remainder wall of the chamberdissolves to allow product to escape, the at least part (20, 27) of thefirst wall (11, 25) which dissolves before the remainder wall dissolvesdefines a releasable part (19, 26), and when the at least part (20, 27)of the first wall (11, 25) dissolves the releasable part (19, 26) isreleased undissolved. 2: The container (1) as defined in claim 1,wherein the releasable part (19, 26) is a panel (19, 26) and the atleast part (20, 27) of the first wall (11, 25) at least partly surroundsthe panel (19, 26) whereby the panel (19, 26) is released when the atleast part (20, 27) of the first wall (11, 25) has dissolved. 3: Thecontainer (201) as defined in claim 1, wherein the at least part of thefirst wall (225) includes at least one clip element (220) which retainsthe releasable part (225) until dissolved. 4: The container (1) asdefined in claim 1, wherein the at least part (20, 27) of the first wall(11, 25) is thinner than the remainder wall of the container. 5: Thecontainer (1) as defined in claim 4, wherein the material thinning (20,27) is arranged on the interior surface of the chamber wall. 6: Thecontainer (1) as defined in claim 1, wherein the container is formed byinjection moulding. 7: The container (1) as defined in claim 1, whereinat least part of the material from which the container is formed ispolyvinyl alcohol. 8: The container (1) as defined in claim 1, whereinat least part of the material from which the container is formed is apolylactic acid.
 9. The container (1) as defined in claim 1, wherein atleast part of the material from which the container is formed isstarch-based. 10: The container (1) as defined in claim 1, wherein thewhole of the container is formed from the same material. 11: Thecontainer (1) as defined in claim 1, wherein the container is flexible.12: (canceled) 13: The container (1) as defined in claim 1 including asecond discrete chamber (130, 131) for containing product, at least apart of a first wall (125 a, 125 b) of said second chamber (130, 131)will dissolve before a remainder wall of the second chamber dissolves toallow product to escape, and the at least part of the first wall (125 a,125 b) of the second chamber which dissolves before the remainder wallthereof dissolves at a different dissolution rate than the dissolutionrate of the at least part (20, 27) of the first wall (11, 25) wherebyproducts in the chambers escape sequentially therefrom. 14: Thecontainer (1) as defined in claim 13, wherein the container is formed byinjection moulding. 15: The container (1) as defined in claim 13,wherein at least part of the material from which the container is formedis polyvinyl alcohol. 16: The container (1) defined in claim 13, whereinat least part of the material from which the container is formed is apolylactic acid.
 17. The container (1) as defined in claim 13, whereinat least part of the material from which the container is formed isstarch-based.